Advice please

[HZSM50]

So they machine them out? The problem I have is the thread that is visible is in good shape. It's very strange!

[Cocko750]

So they machine them out? The problem I have is the thread that is visible is in good shape. It's very strange!

They fill with oil then not cleaned out , hydraulic lock causes them to break out , I'd say someone has found this on a rebuild and cleaned it up as they can't be used and no bits of cast ends up in oil galleries . Later blocks don't have them.